Nearly one in 10 children and teens who play video games show behavioral signs that may indicate addiction, a new study reports.

The study found 8.5% of those who played had at least six of 11 addictive symptoms, including skipping chores and homework for video games, poor test or homework performance and playing games to escape problems. The research, which is published in the May issue of the journal Psychological Science, is based on a 2007 Harris poll of 1,179 U.S. youngsters, the first nationally representative poll on the subject.

Exhibiting six of 11 symptoms can lead to a diagnosis of addiction, such as pathological gambling. Iowa State University researcher Douglas Gentile adopted the addiction criteria for gambling because there is no current medical diagnosis of video-game addiction.

"This study shows there are a substantial number of kids ... taking damage to multiple areas of their life," Gentile says.

On average, the number of symptoms per person was small: boys, typically more than two, girls, less than two. But more boys exhibited at least six symptoms — 12%, vs. 3% of girls. Other symptoms included excessive thinking about games and planning the next opportunity, trying to play less and failing, restlessness or irritability when trying to reduce or stop playing, lying about play time, stealing a game or stealing money to buy a game.

The survey does not end the debate over whether gaming can be addictive in the way gambling or substances can be, Gentile says. Nor does it "tell us who's most at risk (or) how long it lasts. Is it something that only lasts for a couple months when the game system is new, then the kids learn to get it back into balance?"

Jerald Block, a psychiatrist at the Oregon Health Science University, called the study "valuable" to the American Psychiatric Association's decision on whether compulsive computer and Internet use should be considered a mental disorder.

Block, an APA adviser, warns that the study has weaknesses. The research should be replicated because it is supported by the National Institute for Media and the Family, which he likens to a lobbying group. And the survey could have found higher game use because it was collected in January as opposed to summer. It also classifies 8.5% as addicted without a physician interview: "The people they are claiming have a problem, it's not entirely clear that they do have a problem."

Teenage boys who regularly eat fish may be doing their brains some good, a new study suggests.

Swedish researchers found that among nearly 5,000 15-year-old boys they surveyed, those who ate fish more than once per week tended to score higher on intelligence tests three years later.

The findings, published in the journal Acta Pediatrica, add to evidence that fish may indeed be brain food.

Researchers believe that the omega-3 fats found in fish -- particularly oily fish like salmon, mackerel and, to a lesser extent, albacore tuna -- are important to early brain development and to maintaining healthy brain function throughout life.

Past studies have found, for instance, that children whose mothers who ate fish regularly during pregnancy tend to have higher intelligence scores than their peers, and older fish-eaters have been shown to have a lower risk of cognitive impairment.

The new study appears to be the first large-scale one to look at the effects of fish on teenagers' intelligence, lead researcher Dr. Maria Aberg, of Goteborg University, told Reuters Health.

This is important, she explained, because the late-teens are a critical period for the brain "plasticity" that underlies intelligence and emotional and social behavior. Plasticity refers to the brain's ability to reorganize the connections among cells in response to normal experience, like learning a new skill, or to injury.

The findings are based on data from 4,792 male adolescents who completed detailed questionnaires on diet and lifestyle when they were 15 years old, then underwent standard intelligence tests when they were 18.

On average, Aberg's team found, those who ate fish more than once per week scored higher than those who ate fish less than weekly. This remained true when the researchers accounted for several other factors that influence both children's diets and their intelligence scores -- like parents' education levels and the family's socioeconomic status.

"These findings are significant," Aberg said, "because the study was carried out between the ages of 15 and 18, when educational achievements can help to shape the rest of a young man's life."

It's too soon to make specific diet recommendations for teenagers, according to the researcher. "But for the time being," she said, "it appears that including fish in a diet can make a valuable contribution to cognitive performance in male teenagers."